Method and apparatus for a combined exit guide and sectional mill for sidetracking

摘要

A combined casing mill and whipstock or other exit guide is positioned in a drill string assembly used to mill a section of steel casing, which as the section mill mills along the section of casing, allows the exit guide to be transported adjacent the milled-out casing and allows a drill bit and drill string to be run along the surface of the exit guide and into the earth formation. In an alternative embodiment, the combination of the section mill with the exit guide is used in open hole operations having no casing.